Abrading machine



Aug. 9, 1955 H. s. ORR 2,714,787

h ABRADING MACHINE Filed Feb. 15, 1955 2 Sheets-Sheei 1 INVENTO'R.

HOWA R D S O R R HIS ATTORNEY Aug. 9, 1955 H. s. ORR 2,714,787

ABRADING MACHINE Filed Feb. 13, 1955 2 Sheets-Sheet 2 INVENTOR. HOWARD S. ORR

HIS ATTORNEY United States Patent 1 2,714,787 ABRADING MACHINE Howard S. Orr, Pittsburgh, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Application February 13, 1953, Serial No. 336,748 3 Claims. (Cl. 51-142) This invention relates to an abrading machine and more particularly to such a machine having an endless abrasive belt which grinds or polishes the workpiece. In many instances the belt grinds an object which reciprocates beneath the belt. The belt is normally of greater width than the width of the article being abraded and the surface of the belt is worn away across this width, thus providing spaced apart shoulders on the belt. This does not efliciently utilize the belt and also causes other difliculties. Means have been provided to move the belt axially over the supporting rolls, but such means have not been eflective and/or cause damage to the belt. One method of doing this is to slue one of the supporting rolls periodically to move the belt back and forth, but this causes successive stretching of the belt edges with resultant damage thereto. This is especially true when utilizing a high speed belt. Controlled lateral movement of the belt is also advantageous for obtaining particular finishes on the work to be ground.

It is therefore an object of my invention to provide an abrading machine in which a high speed endless belt moves with an oscillatory motion across the face of the work roll.

This and other objects will be more apparent after referring to the following specification and attached drawings, in which:

Figure 1 is a schematic view through the longitudinal center line of the abrading machine;

Figure 2 is a view on an enlarged scale taken on the line II-II of Figure 1;

Figure 3 is a view on an enlarged scale taken on the line III-III of Figure 1; and

Figure 4 is a view on an enlarged scale taken on the line IV-IV of Figure 1.

Referring more particularly to the drawings, reference numeral 2 indicates an endless abrasive belt which passes around a drive roll 4. A motor 6 rotates the drive roll 4 to move the endless belt 2. A tension roll 8, which is preferably a selft-centering roll of the type shown in Lorig Patents Nos. 2,593,157 or 2,593,158 is mounted on the exit side of the roll 4. The roll 8 is mounted on spaced arms 10 which are pivoted on pins 12. An air cylinder 14 which is pivotally mounted on machine frame 16 has its piston rod 18 connected to a member 19 which extends between and connects the arms 10 intermediate their length. A work roll 20, which is cylindrical when grinding flat work, is mounted on the entry side of the roll 4. A self-centering roll 22 of the type shown in the copending applications of Lorig, Serial No. 301,321, filed July 28, 1952 or Serial No. 324,371, filed December 5, 1952 is mounted between the rolls 8 and20. The roll 22 consists of a pair of opposed rotatable rollers 24 mounted on a bent shaft 26 with each of the rollers 24 having a raised flange 28 thereon. The distance between the flanges 28 is equal to or slightly greater than the width of the belt 2. The axes of rotation of the rollers 24 intersect at a point between the rollers and diverge away from the direction of approach of the belt 2. Each of the rollers increases in diameter from its flange 28 toward its inner end. The diameters of the inner ends of the rollers 24 are preferably at least as great and as shown are slightly greater than the diameter of the flanges 28. Means such as a pin 30 is provided to positively cause the rollers 24 to rotate in the same direction and at the same angular velocity. The shaft 26 is mounted on a 2,714,787 Patented Aug. 9, 1955 carriage 32 which in turn is reciprocably mounted in guideways 34 on the frame 16. The bracket 32 is reciprocated by means of a motor 36 through an adjustable crank arm 38 and a connecting link 40. A work table 42 for supporting a workpiece W is mounted beneath the work roll 20. An hydraulic motor 44 is provided to reciprocate the work table 42.. The work roll 20 may be pressed against the workpiece W by conventional mechanism such as a screw 46 connected to each of the roll bearings 48. Each of the screws 46 is in threaded engagement with a worm gear 50. The gear 50 is rotated by means of Worms 52 mounted on a shaft 54. A hand wheel 56 is mounted on the shaft 54 to rotate the shaft and adjust the position of the roll 20.

The operation of the device is as follows:

The work table 42 is reciprocated with the workpiece W thereon beneath the work roll 20 with the belt 2 being rotated by means of the motor 6. Uniform tension is provided on the belt 2 by means of the tension roll 8 in the usual manner. The work roll 20 is moved against the workpiece W by turning the hand wheel 56. The motor 36 through the crank arm 38 and connecting rod 40 reciprocates the self-centering roll 22 axially. Reciprocation of the self-centering roll 22 causes the belt 2 to move across the face of the rolls 4, 8 and 20. In this manner the entire surface of the belt 2 is utilized. For best performance of the belt grinder it is necessary to have a definite relationship between (1) linear belt speed or belt cycles per unit of time, (2) guide roll travel or guide roll cycles per unit of time, and (3) toe-in angle of the two halves of the flanged centering roll. This relationship for various belt speeds and. grinding operations can be determined by trial and error with a minimum amount of difliculty.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. An abrading machine comprising an endless abrasive belt, a drive roll for supporting and driving said belt, a work roll for supporting said belt at the position where a workpiece is being abraded, a self-centering roll around a substantial arc of which the belt passes, said self-centering roll having a raised flange thereon adjacent each end, the distance between said flanges being at least as great as the width of the belt, the axes of said rolls being substantially parallel, and means for axially reciprocating said self-centering roll.

2. An abrading machine according to claim 1 in which said self-centering roll comprises a pair of opposed rotatable rollers, the axes of rotation of said rollers under load intersecting at a point between the rollers and diverging away from the direction of approach of the belt, each of said rollers increasing in diameter from the flange thereon toward its inner end, and means for positively causing said rollers to rotate in the same direction and at the same angular velocity.

3. An abrading machine according to claim 1 in which said self-centering roll comprises a pair of opposed rotatable rollers, a bent shaft for rotatably supporting said rollers, the axes of rotation of said rollers on said shaft intersecting at a point between the rollers and diverging away from the direction of approach of the belt, each of said rollers increasing in diameter from the flange thereon toward its inner end, and means for positively causing said rollers to rotate in the same direction and at the same angular velocity.

References Cited in the file of this patent UNITED STATES PATENTS 2,162,279 Herchenrider June 13, 1939 2,220,268 Olsen Nov. 5, 1940 2,431,795 Elmes Dec. 2, 1947 

